RESUMEN
Brefeldin A induces apoptosis in PC-3 and MCF-7 cells at a concentration of 30 ng/ml. RT-PCR analyses showed up-regulation of CHOP/GADD153 and splicing of XBP-1 mRNA in brefeldin A-treated cells. CHOP promoter-luciferase reporter assays demonstrated activation of AARE, ERSE, and AP-1 elements of CHOP promoter by brefeldin A treatment. The activation of these elements was not affected by preincubation of cells with N-acetyl-cysteine (NAC), L: -buthionine-(S,R)-sulfoximine (BSO), and c-Jun N-terminal kinase (JNK) inhibitor (SP600125), suggesting that activation of CHOP promoter by brefeldin A may not involve oxidative stress or JNK signaling pathway. On the other hand, brefeldin A-induced apoptosis was not affected by NAC and BSO pretreatment, but was completely suppressed by JNK inhibitor pretreatment. Our results suggest that although CHOP is up-regulated by brefeldin A, it is not a major mediator of brefeldin A-induced apoptosis.
Asunto(s)
Brefeldino A/farmacología , Inhibidores de la Síntesis de la Proteína/farmacología , Elementos de Respuesta , Factor de Transcripción CHOP/biosíntesis , Regulación hacia Arriba/efectos de los fármacos , Acetilcisteína/farmacología , Antracenos/farmacología , Apoptosis/efectos de los fármacos , Butionina Sulfoximina/farmacología , Proteínas de Unión al ADN/biosíntesis , Inhibidores Enzimáticos/farmacología , Depuradores de Radicales Libres/farmacología , Humanos , Proteínas Quinasas JNK Activadas por Mitógenos/antagonistas & inhibidores , Factores de Transcripción del Factor Regulador X , Factores de Transcripción/biosíntesis , Proteína 1 de Unión a la X-BoxRESUMEN
PTX1 is a gene identified by subtractive hybridization on the basis that it is expressed in normal prostate and not in prostate carcinoma. It is unrelated to the pituitary homeobox protein (Ptx1 or Pitx1), which regulates pituitary hormone gene expression, and its function is currently unknown. Recently, it was found to be a homolog of the yeast Erv41p, an endoplasmic reticulum (ER) resident protein involved in protein trafficking between ER and Golgi, and was renamed as ERGIC2. Ectopic expression of a partial sequence of PTX1 (Met84 - Leu225) as a VP22-fusion protein in prostate cancer cell line, PC-3, induced cellular senescence. Gene expression microarray analyses showed that interferon-beta (IFN-beta) and a number of IFN-inducible genes, among other genes, were upregulated by the PTX1-VP22 fusion protein. Upregulation of IFN-beta was confirmed by RTPCR and promoter-reporter assay. However, the upregulation of IFN-beta by the PTX1-VP22 fusion protein was not due to nuclear translocation of the PTX1 luminal domain.
Asunto(s)
Interferón beta/genética , Proteínas Nucleares/genética , Neoplasias de la Próstata/genética , Línea Celular Tumoral , Senescencia Celular , Retículo Endoplásmico/metabolismo , Perfilación de la Expresión Génica , Humanos , Masculino , Proteínas Nucleares/metabolismo , Neoplasias de la Próstata/metabolismo , Neoplasias de la Próstata/patología , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/metabolismo , Transfección , Regulación hacia Arriba , Proteínas de Transporte VesicularRESUMEN
Evaluation of needle biopsies and extensive clinicopathological correlation play an important role in the determination of liver allograft dysfunction occurring more than 1 year after transplantation. Interpretation of these biopsies can be quite difficult because of the high incidence of recurrent diseases that show histopathological, clinical, and serological features that overlap with each other and with rejection. Also, more than one insult can contribute to allograft injury. In an attempt to enable centers to compare and pool results, improve therapy, and better understand pathophysiological disease mechanisms, the Banff Working Group on Liver Allograft Pathology herein proposes a set of consensus criteria for the most common and problematic causes of late liver allograft dysfunction, including late-onset acute and chronic rejection, recurrent and new-onset viral and autoimmune hepatitis, biliary strictures, and recurrent primary biliary cirrhosis and primary sclerosing cholangitis. A discussion of differential diagnosis is also presented.
Asunto(s)
Rechazo de Injerto/patología , Trasplante de Hígado/patología , Hígado/patología , Biopsia con Aguja , Diagnóstico Diferencial , Estudios de Seguimiento , Humanos , Factores de Tiempo , Trasplante HomólogoRESUMEN
PTX1 is a gene identified by subtractive hybridization on the basis that it is expressed in normal prostate and not in prostate carcinoma. It encodes a nuclear protein that is downregulated in prostate carcinoma. Expression constructs containing PTX1 cDNA in both sense and antisense orientations were transfected into prostate tumor cell line, PC-3 cells. The effects of the expression of PTX1 and antisense PTX1 on PC-3 cells were examined using cell growth, proliferation, soft agar, invasion chamber, senescence-associated beta-galactosidase, and nude mice assays. Cells transfected with PTX1 construct in the sense orientation were growth-arrested. These cells displayed multiple morphological changes consistent with cellular senescence, including the expression of a senescence-associated beta-galactosidase. On the other hand, expression of antisense PTX1 RNA in PC-3 cells resulted in uncontrolled cell growth and increase of invasive potential. In nude mice, cells expressing antisense PTX1 grew sixfold faster than the control. These results suggest that PTX1 may play an important role in the growth and tumorigenicity of PC-3 cells.